In standard English, “because” is a subordinating conjunction. But due to an emerging use of the term on the internet, it’s also a preposition. “Because” can now precede a noun in order to explain an event or situation. The memetic phrase “because race car” is an example and perhaps the originator of this linguistic tendency. Linguist Stan Carey of the blog Sentence First explains:

The new usage – older than 3–4 years, mind – is what Laura Bailey and Mark Liberman, respectively, have referred to as “because+noun” and “because NOUN”. Liberman says the idiom usually seems to imply “that the referenced line of reasoning is weak”. Sometimes, yes, but it’s also commonly used just for convenience, or effect: No work tomorrow because holidays!; Of course evolution is true, because science.

Because X is fashionably slangy at the moment, diffusing rapidly across communities. It has a snappy, jocular feel, with a syntactic jolt that allows long explanations to be forgone. Because time-strapped. Maybe the causal factor is so obvious as to need no elaboration, or the speaker is distracted or giddy, or online and eager to save effort and move on, or maybe the construction appeals for undefined aesthetic or social reasons.

I suspect that Twitter and text messaging have contributed to this linguistic trend because they tend to condense language. Like Strunk & White’s Rule #17, they encourage writers to “omit needless words.”